Filter
Top Products
Features and Functions 2
34980A User’s Guide 33
RTD Measurements
• The instrument supports RTDs with α = 0.00385 (DIN/IEC 751) using
ITS-90 software conversions or α = 0.00391 using IPTS-68 software
conversions. The default is α = 0.00385.
• The resistance of an RTD is nominal at 0 °C and is referred to as R
0
.
The instrument can measure RTDs with R
0
values from 49Ω to 2.1 kΩ.
• You can measure RTDs using a 2-wire or 4-wire measurement method.
The 4-wire method provides the most accurate way to measure small
resistances. Connection lead resistance is automatically removed using
the 4-wire method.
• For 4-wire RTD measurements, the instrument automatically pairs
channel n in Bank 1 with channel n+20 in Bank 2 (34921A, 34923A) or
n+35 (34922A, 34924A) to provide the source and sense connections.
For example, make the source connections to the HI and LO terminals
on channel 2 in Bank 1 and the sense connections to the HI and LO
terminals on channel 22 (or 37) in Bank 2.
Front Panel Operation: To select the 2-wire or 4-wire RTD function for the
active channel, choose the following items.
DMM or Channel (Configure) > TEMPERATURE > PROBE TYPE > RTD|4W RTD
To select the RTD type (α = 0.00385 or 0.00391) for the active channel,
choose the following item.
RTD TYPE > 0.00391|0.00385
To select the nominal resistance (R
0
) for the active channel, choose the
following item.
RO > 100 OHM
Remote Interface Operation: You can use the CONFigure or MEASure?
command to select the probe type and RTD type. For example, the
following command configures channel 3001 for 2-wire measurements of
an RTD with α = 0.00385 (use “85” to specify α = 0.00385 or “91” to
specify α = 0.00391).
CONF:TEMP RTD,85,(@3001)
You can also use the SENSe command to select the probe type, RTD type,
and nominal resistance. For example, the following command configures
channel 1003 for 4-wire measurements of an RTD with α = 0.00391
(channel 1003 is automatically paired with channel 1023 for the 4-wire
measurement).
SENS:TEMP:TRAN:FRTD:TYPE 91,(@1003)